Rna replicon for improving gene expression and use thereof

An RNA replicon, comprising in a 5′ to 3′ direction:

• a 5′ untranslated region, a 3′ untranslated region, a non-structural protein gene coding region, a subgenomic promoter, and a target gene coding region, wherein any one of mutations (I)-(III) occurs in the non-structural protein gene coding region:
• (I) a mutation in at least one of sites selected from G357, G1569, A1572, and C1575 of a non-structural protein 1 as well as T3922 of a non-structural protein 2, and preferably a simultaneous mutation;
• (II) a mutation in at least one of sites selected from G357, G1569, A1572, and C1575 of a non-structural protein 1 as well as A3821 and T3922 of a non-structural protein 2, and preferably a simultaneous mutation;
• and
• (III) a mutation including but not limited to at least one of sites G3892 of a non-structural protein 2 and A4714 of a non-structural protein 3, and preferably a simultaneous mutation.